Coupling gaskets and associated methods

ABSTRACT

Coupling devices for joining pipe ends include annular gaskets. Example gaskets include pipe interface profiles for sealing performance and manufacturability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/245,189, filed Oct. 3, 2008, which claims the benefit of U.S.Provisional Patent Application No. 60/977,227, filed Oct. 3, 2007, bothof which are hereby specifically incorporated by reference herein intheir entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to couplingdevices used to join sections of pipe and more particularly, toimprovements in the gaskets used in various pipe coupling devices.

2. Description of Related Art

A common type of pipe coupling device used to join two pipes employs ahousing with a C-shaped gasket that is designed to straddle the jointbetween the pipes. The portions of the gasket that resiliently contactthe outer surface of each pipe are often referred to as “sealing lips.”The C-shaped gasket design can provide an effective seal in both vacuumand pressure applications. A cavity created by the inner surface of theC-shaped gasket functions as a pressure reservoir. In positive pressureapplications, pressure within the piping system is applied to theinternal surfaces of the gasket via the cavity formed by the gasket.This positive pressure increases the force of the sealing lips againstthe pipe surfaces. In a vacuum environment, the sealing lips are drawntighter against the pipe surfaces due to the difference in pressurebetween the piping system and atmospheric pressure.

One benefit of these types of coupling devices is that they allow forlimited expansion and contraction of the pipes in the axial direction,while maintaining contact between the sealing lips and each pipe'soutside surface. Movement of the gasket relative to the pipe surfacescan also occur with pressure changes in the piping system. Over time,relative movement between the pipes and the gasket can wear the gasketsealing lips, which can result in leaks. One known solution to thisproblem is to apply a lubricant, such as grease, to the sealing lipsduring the installation process to reduce wear on the sealing lips.Although this has improved the performance of the gaskets, additionalimprovements are needed because the grease can be displaced over timethereby allowing the seals to wear. An additional issue with prior artdesigns is that gaskets can become damaged during installation.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the present invention address issues experiencedwith known coupling devices, some of which are identified above. In oneembodiment, a coupling for joining two pipes positioned end to end insubstantial axial alignment is provided. The coupling device includes: ahousing having a plurality of segments configured to straddle the joint,wherein the housing defines an annular groove; a plurality of fastenersconfigured to connect the plurality of segments; and an annular gasketwith a substantially C-shaped cross-section that defines a housinginterface portion configured to engage the annular groove defined by thehousing and two sealing portions directed inwardly and configured toengage respective outer surfaces of the two pipes, wherein each of thesealing portions includes at least one tapered rib having a verticalcomponent and a horizontal component wherein the vertical component issubstantially perpendicular to the horizontal component.

In another embodiment, an annular gasket is provided. The annular gaskethas a substantially C-shaped cross-section that defines a housinginterface portion formed on the outer surface of the C-shapedcross-section and two sealing portions formed on the outer surface ofthe C-shaped cross-section proximate the respective termination portionsof the C-shaped cross section, wherein each of the sealing portionsincludes at least one tapered rib that includes a vertical component anda horizontal component and wherein the vertical component issubstantially perpendicular to the horizontal component.

In a further embodiment, an asymmetrical annular gasket is provided. Theasymmetrical gasket includes: a substantially L-shaped housing interfaceportion defining a first leg and a second leg; a pipe sealing portionextending substantially perpendicularly from said first leg andincluding a sealing portion defining at least one tapered rib configuredto engage an annular surface; and a flange sealing portion extendingsubstantially perpendicularly from said second leg and configured toengage a flat surface.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a pictorial view of a coupling device 20 in accordance with anembodiment of the present invention;

FIG. 2 is a partial cut-away pictorial view of a coupling device 20joining two pipes in accordance with an embodiment of the presentinvention;

FIG. 3 is a schematic diagram showing a cross-section of a portion of acoupling device 20 and portions of two pipes;

FIG. 4 is a top view of a gasket 40 in accordance with an embodiment ofthe present invention;

FIG. 5 is a cross-section view of the gasket 40 shown in FIG. 4;

FIG. 6 is an enlarged view of the cross-section of the gasket 40 shownin FIGS. 4 and 5;

FIG. 7 is an enlarged view of a cross-section of the pipe interfaceportion 46A of the gasket 40 shown in FIGS. 4-6;

FIG. 8 is a cross-section view of a gasket 70 in accordance with anotherembodiment of the present invention;

FIG. 9 is a cross-section view of a pipe interface portion 80A of thegasket 70 shown in FIG. 8;

FIG. 10 is a pictorial view of a flange coupling device;

FIG. 11 is a cross-section view of the gasket 160 shown in FIG. 10;

FIG. 12 is a schematic diagram of a gasket illustrating some options formovement of mold components used in creating an injection molded gasket;

FIGS. 13 A-E are schematic diagrams illustrating cross-sections ofdifferent types of couplings devices that may include a gasket having atapered rib design in accordance with embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which some, but not allembodiments of the inventions are shown. Indeed, these inventions may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

Various embodiments of the present invention provide improved couplingdevices for joining pipe ends that have improved sealing performanceand/or manufacturability over known pipe coupling devices. One of theimprovements provided by various embodiments of the present invention isa unique design of the gasket. Various embodiments of the gasket includean innovative pipe interface profile that improves the manufacturabilityof the gasket itself and its sealing performance. Specifically, the pipeinterface includes one or more tapered ribs with a geometry that allowsthe use of less complex molds to manufhcture the gasket and also aids indistributing lubricant during the life of the gasket thereby providingimproved sealing performance. The following paragraphs describeembodiments of the present invention in relation to a gasket having aC-shaped cross-section; however, it should be understood that conceptsdescribed herein may be used in conjunction with other types of gaskets.

FIG. 1 illustrates a coupling device 20 in accordance with an embodimentof the present invention. The illustrated device 20 includes a housing25, two fasteners 30A,B, and a gasket 40. In various embodiments, thehousing 25 includes two segments 26A,B, which cooperate to form acylinder. The housing segments include flanges 27A-D that are configuredto receive fasteners 30A,B and facilitate connection of the segments. Itshould be understood that other embodiments of the present invention mayinclude more than two segments to create the cylinder. As will beappreciated by those skilled in the art, couplings for large pipediameters often include a greater number of segments to facilitateinstallation.

The housing 25 may be constructed of grey iron, ductile iron, steelalloys, or other suitable material. The housing 25 may be plated withzinc or other materials such as paint to inhibit corrosion.

FIG. 2 illustrates how the coupling device 20 connects two pipes 10A,B.Generally, the two pipes to be joined are positioned end to end and insubstantial axial alignment. Typically, the pipe ends are spaced apart,but they may be in contact if desired. The pipes 10A,B include grooves12A,B formed or cut into each pipe's outer surface proximate the ends tofacilitate attachment of the coupling device 20 to the pipes 10A,B.Generally, the gasket 40 is positioned such that it straddles the jointbetween the pipes. The housing segments 26A,B are then placed over thegasket and secured together using fasteners.

FIG. 3 provides a schematic of a cross-section of a portion of the pipes10A,B and the coupling device 20. As illustrated, the cross-section ofthe housing 25 is substantially U-shaped with one leg 28A of the “U”engaging a groove 12A in pipe 10A, and the other kg 28B of the “U”engaging a groove 12B formed in pipe 10B. The inner surface of theU-shaped housing defines a groove that is sized and shaped to receive aportion of the gasket 40.

In the illustrated embodiment, the housing 25 is not in rigid contactwith the pipes 10A,B so that the pipes 10A,B are allowed to move or“float” a limited amount. For example, the pipes may be allowed toexpand axially until the edge of the grooves contact an edge of thehousing 25. As will be understood by those skilled in the art, thehousing legs 28A,B may be configured to contact the pipe grooves to forma rigid connection if desired.

Turning to FIGS. 4-7, the gasket 40 is an annular ring having asubstantially C-shaped cross-section. The gasket 40 may be made of anelastomer material such as EPDM, nitrile, fluoro-elastomer or silicon.The gasket may be produced using an injection, extrusion or compressionmolding process.

FIG. 6 illustrates the unique cross-section of the gasket 40 inaccordance with an embodiment of the present invention. The gasket 40has a generally C-shaped cross-section and is substantially symmetricalabout the centerline CL of the gasket. The gasket 40 includes a housinginterface portion 42 and two pipe interface portions 46A,B. The housinginterface portion 42 generally extends from edge 45A to edge 45B alongthe outer surface of the C-shaped gasket 40. This portion of the gasketis sized and shaped to engage the inner surface of the housing 25 asgenerally shown in FIG. 3.

The pipe interface portions 46A,B are located proximate the tips 68A,Bof the C-shaped cross-section of the gasket 40 and are configured toresiliently engage pipe outer surfaces. It should be noted that the pipeinterface portions 46A,B in the illustrated embodiment are substantialmirror images of one another. Accordingly, the following discussionsregarding concepts embodied in the interface portion 46A will also applyto 46B. However, it should be understood that other embodiments of thepresent invention may include pipe interface portions that are notmirror images.

FIG. 7 provides an enlarged view of the interface portion 46A. Theinterface portion 46A extends generally along the outer surface of thegasket 40 from the leading edge 45A and terminates at tip 68A. For theillustrated embodiment, the interface portion 46A includes two taperedrib features 50, 60. Leading into the first rib feature 50 is ahorizontal section 47 that is oriented substantially perpendicular toand directed towards the centerline CL of the gasket 40. The first ribfeature 50 includes a first vertical component 52 and a first horizontalcomponent 54. The first vertical component 52 extends from thehorizontal section 47 in a downward direction and terminates at the edgeof the first horizontal component 54. The first horizontal component 54extends towards the centerline CL such that the vertical component 52and horizontal component 54 are substantially perpendicular. In variousembodiments, the first vertical component 52 may also be substantiallyparallel with the centerline CL of the gasket 40. As will be understoodby those skilled in the art, the tapered rib feature is designed suchthat the vertical component 52 engages the pipe during installation.

The second rib feature 60 includes a second vertical component 62 and asecond horizontal component 64. The second vertical component 62 extendssubstantially perpendicularly from the termination point of the firsthorizontal component 54 in a downward direction and extends to the edgeof the second horizontal component 64. The second horizontal component64 extends towards the centerline CL. The second vertical component 62may be substantially perpendicular to the second horizontal component64. A tapered section 66 extends downward in an obtuse angle from thesecond horizontal section 64 and terminates at the tip 68A. Although theillustrated embodiment shows two tapered rib features, it should beunderstood that other embodiments may comprise one or more tapered ribfeatures. Furthermore, the figures illustrate the rib featuresthemselves as being asymmetrical (e.g., horizontal component longer thanrespective-vertical-component); however, other embodiments may besymmetrical. As will be understood by those skilled in the art, thetapered rib feature is designed such that the vertical component 62engages the associate pipe during installation.

FIG. 8 illustrates the cross-section of another embodiment of the gasket70. The gasket 70 is an annular ring with a substantially C-shapedcross-section. The C-shaped cross-section is substantially symmetricalabout the centerline CL. The gasket 70 includes a housing interfaceportion 72, which extends along the outer surface of the C-shaped gasketfrom edge 75A to edge 75B. Also included in the gasket 70 design are twopipe interface portions 80A,B that extend from the edge 75A,B to thetips 89A,B, respectively, of the C-shaped gasket. The pipe interfaceportions 80A,B are configured to resiliently engage the pipe surfaces.It should be noted that the pipe interface portions 80A,B aresubstantial mirror images of one another. Accordingly, the followingdiscussions regarding the profile of the interface portion 80A will alsoapply to interface portion 80B. However, it should be understood thatother embodiments of the present invention may include pipe interfaceportions that are not mirror images.

FIG. 9 provides an enlarged view of the interface portion 80A. Asillustrated, the interface portion 80A includes two rib features 100,110. Leading into the first rib feature 100 is a horizontal section 82,which extends from edge 75A towards the centerline CL of the gasket.Extending from the horizontal section 82 is a declined section 84, whichextends downwardly at an obtuse angle with respect to the horizontalsection 82 and generally towards the centerline CL. The first ribfeature 100 has a first vertical component 102 and a first horizontalcomponent 104, where the first vertical component 102 may besubstantially parallel with the centerline CL of the gasket 70. Thefirst vertical component 102 extends from the tapered section 84 in adownward direction and terminates at the edge of the first horizontalcomponent 104. The first horizontal component 104 extends towards thecenterline CL in an orientation substantially parallel to the firsthorizontal section 82. In the illustrated embodiment, the first verticaland horizontal components are substantially perpendicular. Extendingfrom the termination of the first horizontal component 104 is a seconddeclined section 86, which extends at an obtuse angle therefrom. As willbe understood by those skilled in the art, the tapered rib feature isdesigned such that vertical component 102 engages the pipe duringinstallation.

The second rib feature 110 includes a second vertical component 112 anda second horizontal component 114. The second vertical component 112extends from the termination point of the second declined section 86 ina downward direction and extends to the edge of the second horizontalcomponent 114. The second horizontal component 114 extends towards thecenterline CL in an orientation substantially parallel to the firsthorizontal section 82 and terminates at tip 89A. Although the embodimentillustrated in FIGS. 8 and 9 includes two tapered rib features, itshould be understood that other embodiments may include one or moretapered rib features.

FIG. 10 illustrates a flange coupling device 150 in accordance with anembodiment of the present invention. Flange couplings are used toprovide a fluid tight seal between a pipe end and a mating flange. Theillustrated flange coupling 150 includes two housing segments 152A,B andtwo fasteners 154A,B for securing the segments together. The flangecoupling device 150 also includes an annular gasket 160 for providingthe fluid tight seal. The gasket 160 is an annular ring has anasymmetrical cross-section.

FIG. 11 illustrates the cross-section of the gasket 160, which includesa housing interface portion 162, a pipe interface portion 170 and aflange interface portion 190. The housing interface portion 162 issubstantially L-shaped and extends from edge 165 to edge 167 along theouter surface of the gasket 160. This portion of the gasket is sized andshaped to engage the inner surface of the housing segments 152A,B. Thepipe interface portion 170 extends from edge 167 to tip 185 and isconfigured to resiliently engage the outer surface of the pipe beingjoined.

In the illustrated embodiment, the pipe interface portion 170 includes atapered rib feature 172, which comprises a declined component 176 and ahorizontal component 178, Leading into the tapered rib feature 172 is afirst horizontal section 174 that extends from edge 167 and is orientedsubstantially perpendicular to the adjacent housing interface portion.This horizontal section 174 terminates into the first declined component176 of the tapered rib feature 172. The declined component 176 isoriented at an obtuse angle with respect to the horizontal section 174and terminates in the horizontal component 178 of the tapered ribfeature 172. The horizontal component 178 is substantially parallel tothe horizontal section 174. The horizontal component 178 terminates in aradius 180, which itself terminates in a declined section 182. Thedeclined section 182 terminates at the tip 185. Although the illustratedembodiment shows a single tapered rib feature, it should be understoodthat other embodiments may comprise one or more tapered rib features.

The flange interface portion extends from edge 165 to tip 192 at anobtuse angle from the adjacent housing interface portion. The flangeinterface portion extends into a radius 194 which extends inwardly.

Methods of Use

As noted, various embodiments of the coupling device 20 may be used tojoin two pipes. As a first step in installing the coupling device 20, alubricant, such as grease, is applied to the interface portions 46A,B ofthe gasket 40. The gasket 40 is then slid onto the outer surface of pipe10A, such that both interface portions 46A,B are in contact with theouter surface of pipe 10A. As will be understood by those skilled in theart, the vertical components of the tapered ribs on interface portion46A engage the pipe 10A during installation.

Next, a second pipe, 10B, is placed end to end in substantial axialalignment with pipe 10A such that a gap is present between the ends. Thegasket is then slid towards pipe 10B until the gasket is substantiallycentered over the gap between the pipe ends such that interface portion46A is in contact with pipe 10A and interface portion 46B is in contactwith pipe 10B. As will be understood by those skilled in the art, thevertical components of the tapered ribs on interface portion 46B engagethe pipe 10B as the gasket is slid towards pipe 10B.

Once the gasket is positioned, each segment of the housing is positionedover the gasket and the segments loosely connected using fasteners.After all of the housing segments are positioned, the fasteners may betightened such that each segment is rigidly connected to its adjacentsegment(s). A cut-away view of a finished coupling device 20 attached totwo pipes is illustrated in FIG. 2.

As is apparent by the installation procedure described above, the gasketis repositioned several times during the coupling process. A benefit ofthe unique ribbed profiles described herein is that a portion of theapplied grease may be retained between the two ribs as well as betweenthe ribs and other features such as the leading edge 45 and tip 68A.This creates a small reservoir that can replenish grease or otherlubricant to the surface of the pipe over time to improve the durabilityof the seal.

An additional benefit of the tapered rib geometry is that it addsflexibility to the design of molds needed to create the gasket. As oneof ordinary skill in the art will appreciate, an injection mold may openand close in a direction substantially parallel (“B”) or perpendicular(“A”) to the centerline of the gasket as generally shown in FIG. 12 dueto the tapered rib geometry profile. If other rib profiles were used,the mold would likely have to open and close in direction “C” to reducethe chance of deformation of ribs caused by the mold dragging across therib profile when opened to allow the gasket to be removed. It should benoted that molds used to produce gaskets with the tapered ribbedprofiles describe herein may open and close in any direction betweendirection “A” and “B” as desired.

Many modifications and other embodiments of the inventions set forthherein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. For example,concepts disclosed herein may be used in conjunction with various pipecouplings marked by Anvil Industries, Inc., such as Roughneck®, EndGuard®, Flush Gap®, Reducing, and Flange couplings illustrated in FIGS.13A-E, respectively.

It is to be understood that the inventions are not to be limited to thespecific embodiments disclosed and that modifications and otherembodiments are intended to be included within the scope of the appendedclaims. Although specific terms are employed herein, they are used in ageneric and descriptive sense only and not for purposes of limitation.

That which is claimed:
 1. An asymmetrical annular gasket comprising: asubstantially L-shaped housing interface portion defining a first legand a second leg; a pipe sealing portion extending from said first legand including a tapered rib extending from the pipe sealing portion, thetapered rib when not engaged having a substantially horizontal componentsurface extending in a substantially axial direction, a declinedcomponent surface intersecting the substantially horizontal componentsurface, a radius section intersecting the substantially horizontalcomponent surface and extending at least partially radially inward fromthe substantially horizontal component surface, and a declined sectionextending radially inwardly from the radius section at a different anglethan the radius section, the declined component surface when not engagedextending at least partially radially outward from the substantiallyhorizontal component surface and intersecting a horizontal sectionhaving a surface extending in a substantially axial direction; and aflange sealing portion extending from said second leg.
 2. The annulargasket of claim 1, wherein the declined component surface and thesubstantially horizontal component surface of the tapered rib havedifferent lengths.
 3. The annular gasket of claim 1, wherein: the firstleg includes a first surface at one axial side of the annular gasket andextending substantially radially; the second leg includes a secondsurface extending substantially axially and facing radially outward; thepipe sealing portion extends substantially perpendicularly from thefirst surface; and the flange sealing portion extends at an angle in aradially inward direction from the second surface.
 4. The annular gasketof claim 1, wherein the horizontal section of the pipe sealing portionis axially outer from the tapered rib when not engaged.
 5. The annulargasket of claim 4, wherein the horizontal section of the pipe sealingportion is radially outer from the horizontal surface of the tapered riband intersects an axially outer edge of the pipe sealing portion.
 6. Theannular gasket of claim 1, wherein the declined section terminates in atip at a radially innermost end of the pipe sealing portion.
 7. Theannular gasket of claim 6, wherein the horizontal section has a radiusequal to a radius of the tip when the gasket engages a pipe outersurface.
 8. The annular gasket of claim 6, further comprising a curvedsection extending at least partially radially outwardly from the tipopposite the declined section.
 9. The annular gasket of claim 1, whereinthe declined section extends from the radius section at an angle betweenthe axial direction and the angle of the radius section.
 10. The annulargasket of claim 1, wherein the substantially horizontal componentsurface, declined component surface, radius section, and declinedsection contact a pipe outer surface when the gasket engages the pipeouter surface.
 11. The annular gasket of claim 1, further comprising avertical sidewall extending radially outward from the substantiallyhorizontal component surface and orthogonal to the substantiallyhorizontal component surface.